1. Field of the Invention
This invention relates to an automatic transmission for a motor vehicle that includes planetary gearsets and clutches and brakes whose state of engagement and disengagement determines speed ratios produced by the transmission.
2. Description of the Prior Art
In a front wheel drive vehicle, the axial space available for the transmission is limited by the width of the engine compartment and the length of the engine. In addition, the trend to increase the number of ratios available generally increases the number of components required. For these reasons, it is desirable to position components concentrically in order to minimize axial length. The ability to position components concentrically is limited, however, by the need to connect particular components mutually and to the transmission case.
Furthermore, it is desirable for the output element to be located near the center of the vehicle, which corresponds to the input end of the gear box. An output element located toward the outside of the vehicle may require additional support structure and add length on the transfer axis. With some kinematic arrangements, however, the need to connect certain elements to the transmission case requires that the output element be so located.
One of the transmission control devices, such as the D brake, may be used only as a latching device rather than as a dynamic device. To minimize parasitic viscous drag loss produced in the control device, it would be better if the brake were a latching mechanism rather than a hydraulically-actuated friction brake having interleaved discs and spacer plates.